The family of alternating electric fields ion traps for ion storage and mass analysis includes 3-dimension rotational symmetric ion traps (3D-Rot. Sym.IT) and linear ion traps (LIT). In a 3-dimension rotational symmetric ion trap, ions are trapped around the center of the trap. Due to the space-charge effect, the number of ions which may be stored in a 3-dimension rotation symmetric ion trap is limited. Although a large number of ions can be successfully trapped inside a 3-dimension rotational symmetric ion trap, the severe charge-charge interaction between multiple ions will destroy the mass resolution in mass analysis procedure. In a linear trap, ions are stored around a middle axis of the trap. Accordingly, the number of trapped ions within a linear ion trap increases greatly under the same volume density of space charge. Previous research shows that a linear ion trap can trap more than 10 times the number of ions a same scale 3-dimension rotational symmetric ion trap can without obvious space charge effect, and more than a million ions can be trapped with a single ion injection procedure for the next step mass spectrometry analysis. But, under certain conditions, linear ion traps cannot meet all needs. For example, the electric signal of an ion stream in a linear ion trap still needs to be amplified by a high-gain electron multiplier for detection. For the detection of an infinitesimal analyte, the effective signal covered by noises millions folds of analyte cannot be detected. It is therefore necessary to develop greater storage ion traps.
It is known that the storage of trapped ions can be multiplied by simply arraying a group of linear ion traps (see, for example, US Patent Application Publication No. US2004/0135080A1). However, the cost of making a group of simply arrayed linear ion traps is relatively high. Furthermore, ions trapped within different linear ion traps in this type of array eject through corresponding outlet slits of respective ion traps. Accordingly, an ion detector with great receive surface is needed to receive simultaneous ion signals.